%0 Generic
%A C.-M., Tsai
%A A.M., Riestra
%A S.R., Ali
%A J.J., Fong
%A J.Z., Liu
%A G., Hughes
%A A., Varki
%A V., Nizet
%D 2019
%T Supplementary Material for: Siglec-14 Enhances NLRP3-Inflammasome Activation in Macrophages
%U https://karger.figshare.com/articles/dataset/Supplementary_Material_for_Siglec-14_Enhances_NLRP3-Inflammasome_Activation_in_Macrophages/11323454
%R 10.6084/m9.figshare.11323454.v1
%2 https://karger.figshare.com/ndownloader/files/20080862
%K Siglec
%K Interleukin-1β
%K Caspase-1
%K Inflammasome
%K Macrophages
%K Innate immunity
%K Vimentin
%X Pathogenic microorganisms are sensed by the inflammasome, resulting in the release of the pro-immune and proinflammatory cytokine interleukin-1β (IL-1β). In humans, the paired sialic acid-binding Ig-like lectin receptors Siglec-5 (inhibitory) and Siglec-14 (activating) have been shown to have reciprocal roles in regulating macrophage immune responses, but their interaction with IL-1β signaling and the inflammasome has not been characterized. Here we show that in response to known inflammasome activators (ATP, nigericin) or the sialic acid-expressing human bacterial pathogen group B Streptococcus (GBS), the presence of Siglec-14 enhances, whereas Siglec-5 reduces, inflammasome activation and macrophage IL-1β release. Human THP-1 macrophages stably transfected with Siglec-14 exhibited increased caspase-1 activation, IL-1β release and pyroptosis after GBS infection, in a manner blocked by a specific inhibitor of nucleotide-binding domain leucine-rich repeat protein 3 (NLRP3), a protein involved in inflammasome assembly. Another leading pathogen, Streptococcus pneumoniae, lacks sialic acid but rather prominently expresses a sialidase, which cleaves sialic acid from macrophages, eliminating cis- interactions with the lectin receptor, thus attenuating Siglec-14 induced IL-1β secretion. Vimentin, a cytoskeletal protein released during macrophage inflammatory activation is known to induce the inflammasome. We found that vimentin has increased interaction with Siglec-14 compared to Siglec-5, and this interaction heightened IL-1β production by Siglec-14-expressing cells. Siglec-14 is absent from some humans because of a SIGLEC5/14 fusion polymorphism, and we found increased IL-1β expression in primary macrophages from SIGLEC14+/+ individuals compared to those with the SIGLEC14–/+ and SIGLEC14–/– genotypes. Collectively, our results identify a new immunoregulatory role of Siglec-14 as a positive regulator of NLRP3 inflammasome activation.
%I Karger Publishers